Artículos y presentaciones en Congresos

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  • Artículo
    Acceso Abierto
    Actividad antimicrobiana de germicidas halogenados frente a aislamientos hospitalarios
    (2001) Magariños, María del Carmen; Penacca, Alejandra C.; Castelo, Sandra M.; Martínez, Anabela M.; Demartini, Eduardo A.; Landriel, Lorena; Reynaldo, Mirta Beatriz
    Antiseptics and disinfectants are extensively used in hospitals and health care settings for a variety of topical and hard-surface applications. In particular, they are essential part of infection control practices and in the prevention of nosocomial infections. Despite this, few is known about the mode of action of these biocides with respect to antibiotics. In general, the antimicrobial activity can be influenced by many factors such as formulation effects, presence of organic matter, synergy, temperature, dilution and test method. The widespread use of antiseptics and disinfectant products has prompted some speculation on the development of microbial resistance, in particular cross-resistance to antibiotics. The aim of this study was to evaluate microbiological resistance to halogenated compounds by studying the behaviour of the grampositive and gramnegative clinical isolates against halogenated biocides usually applied, with and without organic substance and applying distilled water, potable water and water of 300 ppm hardness as dilution means. The results indicate that the hospital microorganisms show a higher resistance to the biocides than the strain Staphylococcus aureus ATCC 6538, although the effective concentration in clean conditions was lesser than the recommended ones, for all the dilution means. In presence of organic matter the antimicrobial activity was reduced in accordance with the bactericidal concentration of each microorganisrn, due to the oxidant action of these disinfectants
  • Artículo
    Acceso Abierto
    Is Oreochromis niloticus invading the Samborombón Bay, Río de la Plata, Argentina?
    (Museo Argentino de Ciencias Naturales "B. Rivadavia" (MACN), 2010) García, Mirta L.; Cuello, Mariela; Solari, Agustín; Milessi, Andres Conrado; Cortés, Federico; Bruno, Ignacio M.; Zapata, María F.
    The Nile tilapia (Oreochromis niloticus) is a species widely cultivated worldwide. In recent decades it was an increasing development of fish farming of this species and the red variety in Argentina and Uruguay. From January to March 2010, four specimens of O. niloticus were captured in the south boundary of Samborombón Bay (S 36° 17´- W 56° 46´), which is the external sector of the Río de la Plata. Probably the collected specimens were released accidentally from hatcheries placed on the banks of aquatic environments in communication with the Samborombón Bay. The patterns and mechanisms of species dispersal are of significant interest, while the interactions among factors determining invasion success often remain poorly understood. Invasion success is influenced by the ability of invading specie to withstand, interactions with native species and oceanographic characteristics of the new habitat. Of four specimens obtained two were females, one in spawning stage. This is the first record of Nile tilapia from a natural environment in Argentina and could indicate the beginning of a new invasion by a non native species.
  • Artículo
    Acceso Abierto
    Effect of Pioglitazone on the Fructose-Induced Abdominal Adipose Tissue Dysfunction
    (Hindawi Publishing Corporation, 2012) Alzamendi, Ana; Giovambattista, Andrés; Garcia, María Elisa; Rebolledo, Oscar R.; Gagliardino, Juan José; Spinedi, Eduardo
    Aim. To test the potential role of PPARγ in the endocrine abdominal tissue dysfunction induced by feeding normal rats with a fructose rich diet (FRD) during three weeks. Methodology. Adult normal male rats received a standard commercial diet (CD) or FRD, (10% in drinking water) without or with pioglitazone (PIO) (i.p. 0.25mg/Kg BW/day; CD-PIO and FRD-PIO). Thereafter, we measured circulating metabolic, endocrine, and oxidative stress (OS) markers, abdominal adipose tissue (AAT) mass, leptin (LEP) and plasminogen activator inhibitor-1 (PAI-1) tissue content/expression, and leptin release by isolated adipocytes incubated with different concentrations of insulin. Results. Plasma glucose, insulin, triglyceride, TBARS, LEP, and PAI-1 levels were higher in FRD rats; PIO coadministration fully prevented all these increments. AAT adipocytes from FRD rats were larger, secreted a higher amount of LEP, and displayed decreased sensitivity to insulin stimulation; these effects were significantly ameliorated by PIO. Whereas AAT LEP and PAI-1 (mRNA) concentrations increased significantly in FRD rats, those of insulin-receptor-substrate- (IRS-) 1 and IRS-2 were reduced. PIO coadministration prevented FRD effects on LEP, PAI-1, and IRS-2 (fully) and IRS-1 (partially) mRNAs in AAT. Conclusion. PPARγ would play a relevant role in the development of the FRD-induced metabolicendocrine dysfunction.
  • Artículo
    Acceso Abierto
    Oral Metformin Treatment Prevents Enhanced Insulin Demand and Placental Dysfunction in the Pregnant Rat Fed a Fructose-Rich Diet
    (Hindawi Publishing Corporation, 2012) Alzamendi, Ana; Del Zotto, Héctor; Castrogiovanni, Daniel; Romero, José; Giovambattista, Andrés; Spinedi, Eduardo
    The intake of a fructose-rich diet (FRD) in the normal female rat induces features similar to those observed in the human metabolic syndrome phenotype. We studied the impact of FRD administration to mothers on pregnancy outcome. On gestational day (Gd) zero rats were assigned to either group: ad libitum drinking tap water alone (normal diet, ND) or containing fructose (10% w/vol; FRD) through pregnancy; all rats were fed a Purina chow diet ad libitum ND and FRD rats were daily cotreated or not with metformin (60 mg/Kg/day oral; ND + MF and FRD + MF) and submitted to a high glucose load test on Gd 14. Additionally, placentas from different groups were studied on Gd 20. Data indicated that: (1) although FRD rats well tolerated glucose overload, their circulating levels of insulin were significantly higher than in ND rats; (2) the mesometrial triangle blood vessel area was significantly lower in placentas from FRD than ND dams; (3) the detrimental effects of FRD administration to mothers were ameliorated by metformin cotreatment. Our study suggests that excessive intake of fructose during pregnancy enhanced the risk for developing gestational diabetes and subsequent preeclampsia, and that metformin prevented the poor pregnancy outcome induced by FRD.
  • Artículo
    Acceso Abierto
    Ghrelin Indirectly Activates Hypophysiotropic CRF Neurons in Rodents
    (2012) Cabral, Agustina; Suescun, Olga; Zigman , J.M.; Perelló, Mario
    Ghrelin is a stomach-derived hormone that regulates food intake and neuroendocrine function by acting on its receptor, GHSR (Growth Hormone Secretagogue Receptor). Recent evidence indicates that a key function of ghrelin is to signal stress to the brain. It has been suggested that one of the potential stress-related ghrelin targets is the CRF (Corticotropin-Releasing Factor)-producing neurons of the hypothalamic paraventricular nucleus, which secrete the CRF neuropeptide into the median eminence and activate the hypothalamic-pituitary-adrenal axis. However, the neural circuits that mediate the ghrelin-induced activation of this neuroendocrine axis are mostly uncharacterized. In the current study, we characterized in vivo the mechanism by which ghrelin activates the hypophysiotropic CRF neurons in mice. We found that peripheral or intra-cerebro-ventricular administration of ghrelin strongly activates c-fos – a marker of cellular activation – in CRFproducing neurons. Also, ghrelin activates CRF gene expression in the paraventricular nucleus of the hypothalamus and the hypothalamic-pituitary-adrenal axis at peripheral level. Ghrelin administration directly into the paraventricular nucleus of the hypothalamus also induces c-fos within the CRF-producing neurons and the hypothalamic-pituitary-adrenal axis, without any significant effect on the food intake. Interestingly, dual-label immunohistochemical analysis and ghrelin binding studies failed to show GHSR expression in CRF neurons. Thus, we conclude that ghrelin activates hypophysiotropic CRF neurons, albeit indirectly.
  • Artículo
    Acceso Abierto
    Fructose Rich Diet-Induced High Plasminogen Activator Inhibitor-1 (PAI-1) Production in the Adult Female Rat: Protective Effect of Progesterone
    (MDPI (Multidisciplinary Digital Publishing Institute), 2012) Castrogiovanni, Daniel; Alzamendi, Ana; Ongaro, Luisina; Giovambattista, Andrés; Gaillard, Rolf; Spinedi, Eduardo
    The effect of progesterone (P4) on fructose rich diet (FRD) intake-induced metabolic, endocrine and parametrial adipose tissue (PMAT) dysfunctions was studied in the adult female rat. Sixty day-old rats were i.m. treated with oil alone (control, CT) or containing P4 (12 mg/kg). Rats ate Purina chow-diet ad libitum throughout the entire experiment and, between 100 and 120 days of age drank ad libitum tap water alone (normal diet; CT-ND and P4-ND) or containing fructose (10% w/v; CT-FRD and P4-FRD). At age 120 days, animals were subjected to a glucose tolerance test or decapitated. Plasma concentrations of various biomarkers and PMAT gene abundance were monitored. P4-ND (vs. CT-ND) rats showed elevated circulating levels of lipids. CT-FRD rats displayed high (vs. CT-ND) plasma concentrations of lipids, leptin, adiponectin and plasminogen activator inhibitor-1 (PAI-1). Lipidemia and adiponectinemia were high (vs. P4-ND) in P4-FRD rats. Although P4 failed to prevent FRD-induced hyperleptinemia, it was fully protective on FRD-enhanced plasma PAI-1 levels. PMAT leptin and adiponectin mRNAs were high in CT-FRD and P4-FRD rats. While FRD enhanced PMAT PAI-1 mRNA abundance in CT rats, this effect was absent in P4 rats. Our study supports that a preceding P4-enriched milieu prevented the enhanced prothrombotic risk induced by FRD-elicited high PAI-1 production.
  • Artículo
    Acceso Abierto
    Determinantes sociales adversos y riesgo para anomalías congénitas seleccionadas
    (Sociedad Argentina de Pediatría (SAP), 2014) Pawluk, Mariela S.; Campaña, Hebe Edith; Gili, Juan; Comas, Belén; Giménez, Lucas; Villalba, María I.; Scala, Sandra C.; Poletta, Fernando A.; López Camelo, Jorge Santiago
    Introducción. Diferentes trabajos han relacionando condiciones sociales adversas a nivel familiar y regional con resultados perinatales (mortalidad neonatal, bajo peso y prematuridad); sin embargo, pocos estudiaron el efecto de la pobreza sobre anomalías congénitas. Objetivo. Evaluar el riesgo de ocurrencia de 25 anomalías congénitas y determinantes sociales adversos según el nivel socioeconómico de la familia y de la región. Población y métodos. Estudio caso-control exploratorio, en el que se utilizaron datos del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC). La muestra consistió en 3786 recién nacidos vivos con una única malformación y 13 344 controles, seleccionados entre 546 129 nacimientos, ocurridos en 39 hospitales de Argentina durante el período 1992-2001. Se estimaron los riesgos (OR) directos, indirectos (a través de la región de residencia) y la interacción entre el nivel socioeconómico individual y residencial para cada uno de los 25 defectos congénitos. Resultados. Los defectos labio leporino con/sin paladar hendido (OR= 1,43) y comunicación interventricular (OR= 1,38) mostraron un riesgo significativamente mayor en el nivel socioeconómico más bajo. Los niveles socioeconómicos bajos se asociaron de manera significativa con una mayor frecuencia de consanguinidad parental, ancestros nativos, edad materna menor de 19 años, más de 4 embarazos, bajo número de visitas prenatales y residencia en regiones desfavorables. Conclusión. La fisura labial con o sin paladar hendido y los defectos del tabique interventricular estuvieron asociados significativamente con un nivel socioeconómico más bajo. La falta de planificación familiar, de control prenatal y la exposición a agentes ambientales o teratógenos pueden explicar estos hallazgos.
  • Artículo
    Acceso Abierto
    Linajes paternos del Gran Chaco, un abordaje desde el ADN
    (2014) Jurado Medina, Laura Smeldy; Ramallo, Virginia; Calandra, Horacio; Lamenza, Guillermo; Braunstein, José; Salceda, Susana; Bailliet, Graciela
    La región no recombinante del cromosoma Y ha sido exitosamente utilizada para reconocer la estructura genética de los linajes paternos de poblaciones humanas. Este trabajo se integra al proyecto multidisciplinario “De las historias étnicas a la prehistoria en el Gran Chaco”, involucra el estudio de individuos de diversa filiación étnica y se propone reconocer la estructuración en la fracción nativa de los linajes paternos. Tal información dará cuenta de la dinámica poblacional y de los patrones de distribución aportando así, elementos clarificadores de la compleja configuración de las poblaciones chaqueñas. En los 118 individuos analizados se identificaron 82 linajes, de los cuales 22% estuvieron presentes en más de un individuo dentro de una población o entre poblaciones, en ocasiones distantes geográficamente. El coeficiente de diferenciación entre poblaciones fue el mayor encontrado (FST = 21%) en linajes autóctonos de poblaciones de Argentina (FST = 3%). La red de haplotipos demuestra que los linajes presentan una subestructuración en 3 ramas principales, en cada una de las mismas participan linajes de distintos grupos, reflejando la ausencia de aislamiento entre los mismos y planteando interesantes interrogantes a la luz de los datos arqueológicos y etnolingüísticos.
  • Artículo
    Acceso Abierto
    X-ray structure of the mature ectodomain of phogrin
    (2015) Noguera, M.E.; Primo, María Evangelina; Jakoncic, J.; Solimena, M.; Poskus, E.; Ermácora, Mario
    Phogrin/IA-2β and ICA512/IA-2 are two paralogs receptor-type protein-tyrosine phosphatases (RPTP) that localize in secretory granules of various neuroendocrine cells. In pancreatic islet β-cells, they participate in the regulation of insulin secretion, ensuring proper granulogenesis, and β-cell proliferation. The role of their cytoplasmic tail has been partially unveiled, while that of their luminal region remains unclear. To advance the understanding of its structure-function relationship, the X-ray structure of the mature ectodomain of phogrin (ME phogrin) at pH 7.4 and 4.6 has been solved at 1.95- and 2.01-Å resolution, respectively. Similarly to the ME of ICA512, ME phogrin adopts a ferredoxin-like fold: a sheet of four antiparallel β-strands packed against two α-helices. Sequence conservation among vertebrates, plants and insects suggests that the structural similarity extends to all the receptor family. Crystallized ME phogrin is monomeric, in agreement with solution studies but in striking contrast with the behavior of homodimeric ME ICA512. The structural details that may cause the quaternary structure differences are analyzed. The results provide a basis for building models of the overall orientation and oligomerization state of the receptor in biological membranes.
  • Artículo
    Acceso Abierto
    Neonatal androgenization-induced early endocrine metabolic and ovary misprogramming in the female rat
    (2015) Ongaro, Luisina; Salvetti, N.; Giovambattista, Andrés; Spinedi, E.; Ortega, H.
    AIM: Androgen excess predisposes the organism to develop metabolic-endocrine and reproductive dysfunctions, among them the development of a phenotype resembling that ofhumanPolycystic Ovary Syndrome(PCOS).METHODS: We analyzed the impact of a single neonatal (5day-old)testosterone propionate(TP; s.c. 1.25mg/female pup) dose on: a) several metabolic-endocrine activities and b) ovarian steroidogenic and granulosacell(GC) functions and also follicular population in juvenile and adult TP and control (CT)rats. KEY FINDINGS: Compared to CTrats, TPanimalswere characterized by: a) acceleratedgrowth, hyperadiposity and hyperleptinemia, b) very early (pre-weaning age) vaginal opening, c)hyperinsulinemiain adult life, d) dysfunctional ovariansteroidogenesis, e) conserved GC functionality in both juveniles (in vitro) and adults (in vivo), and f)estrous cyclesarrested atestrus. Finally, histological studies of the ovaries indicated that in TP (vs. CT)rats: i) primary and antral follicle frequencies were 3- and 15-fold higher and lower, respectively, in juveniles and ii) secondary and atretic follicle frequencies were 3- and 5-fold lower and higher, respectively, in adults. Large cystic images without corpus luteum were observed in the ovaries from adult TPratsonly. SIGNIFICANCE: Our results strongly suggest that transient neonatal hyperandrogenemia induced early misprogramming of metabolic-endocrine and ovarian (steroidogenesis/folliculogenesis) functions. Conversely, TPratspreserved their ovary GC endocrine function. Our results further support the high risk of developingovarian hyperstimulation syndromeforinfertilewomen with transient/chronic hyperandrogenemia (PCOS) subjected to assisted reproductive technologies.
  • Artículo
    Acceso Abierto
    Ghrelin's orexigenic effect is modulated via a serotonin 2C receptor interaction
    (American Chemical Society, 2015) Schellekens, Harriet; De Francesco, Pablo; Kandil, Dalia; Theeuwes,Wessel F.; McCarthy, Triona; van Oeffelen,Wesley E.P.A.; Perelló, Mario; Giblin, Linda; Dinan, Timothy G.; Cryan, John F.
    Understanding the intricate pathways modulating appetite and subsequent food intake is of particular importance considering the rise in obesity incidence across the globe. The serotonergic system, specifically the 5-HT2C receptor, has shown to be of critical importance in the regulation of appetite and satiety. The GHS-R1a receptor is another key receptor wellknown for its role in the homeostatic control of food intake and energy balance. We recently showed compelling evidence for an interaction between the GHS-R1a receptor and the 5-HT2C receptor in an in vitro cell line system heterologously expressing both receptors. Here, we investigated this interaction further. First, we show that the GHS-R1a/5-HT2C dimer-induced attenuation of calcium signalling is not due to coupling to GαS, as no increase in cAMP signalling is observed. Next, flowcytometry fluorescence resonance energy transfer (fcFRET) is used to further demonstrate the direct interaction between the GHS-R1a receptor and 5-HT2C receptor. In addition, we demonstrate co-localized expression of the 5-HT2C and GHS-R1a receptor in cultured primary hypothalamic- and hippocampal rat neurons, supporting the biological relevance of a physiological interaction. Furthermore, we demonstrate that when 5-HT2C receptor signalling is blocked, ghrelin’s orexigenic effect is potentiated in vivo. In contrast, the specific 5-HT2C receptor agonist lorcaserin, recently approved for the treatment of obesity, attenuates ghrelin-induced food intake. This underscores the biological significance of our in vitro findings of 5-HT2C receptor-mediated attenuation of GHS-R1a receptor activity. Together, this study demonstrates, for the first time, that the GHS-R1a/5-HT2C receptor interaction translates into biological significant modulation of ghrelin’s orexigenic effect. This data highlights the potential development of a combined GHS-R1a and 5-HT2C receptor treatment strategy in weight management.
  • Artículo
    Acceso Abierto
    Escalation in high fat intake in a binge eating model differentially engages dopamine neurons of the ventral tegmental area and requires ghrelin signaling
    (2015) Valdivia Torres, Lesly Spring; Cornejo, María P.; Reynaldo, Mirta Beatriz; De Francesco, Pablo; Perelló, Mario
    Binge eating is a behavior observed in a variety of human eating disorders. Ad libitum fed rodents daily and time-limited exposed to a high-fat diet (HFD) display robust binge eating events that gradually escalate over the initial accesses. Intake escalation is proposed to be part of the transition from a controlled to a compulsive or loss of control behavior. Here, we used a combination of behavioral and neuroanatomical studies in mice daily and time-limited exposed to HFD to determine the neuronal brain targets that are activated – as indicated by the marker of cellular activation c-Fos – under these circumstances. Also, we used pharmacologically or genetically manipulated mice to study the role of orexin or ghrelin signaling, respectively, in the modulation of this behavior. We found that four daily and time-limited accesses to HFD induce: (i) a robust hyperphagia with an escalating profile, (ii) an activation of different sub-populations of the ventral tegmental area dopamine neurons and accumbens neurons that is, in general, more pronounced than the activation observed after a single HFD consumption event, and (iii) an activation of the hypothalamic orexin neurons, although orexin signaling blockage fails to affect escalation of HFD intake. In addition, we found that ghrelin receptor-deficient mice fail to both escalate the HFD consumption over the successive days of exposure and fully induce activation of the mesolimbic pathway in response to HFD consumption. Current data suggest that the escalation in high fat intake during repeated accesses differentially engages dopamine neurons of the ventral tegmental area and requires ghrelin signaling.
  • Artículo
    Acceso Abierto
    Riesgo de anomalías congénitas en grupos étnicos de Sudamérica
    (2015) Villalba, María I.; Campaña, Hebe Edith; Scala, Sandra C.; Pawluk, Mariela S.; López Camelo, Jorge Santiago
    El objetivo del trabajo fue estimar el riesgo de defectos congénitos según condición étnica de los padres del recién nacido. Fueron seleccionados 20.940 neonatos con 10 anomalías congénitas específicas y un grupo similar de controles, clasificados según su condición étnica. Se estimaron los riesgos de las 10 anomalías congénitas aisladas mediante métodos de regresión logística, ajustando los riesgos por índices de propensión (Propensity Score) utilizando la prueba de Mantel-Haenszel. Los resultados del presente trabajo mostraron que en europeos latinos existe un mayor riesgo de tener un recién nacido con espina bífida, sindactilia 2-3 del pie e hipospadias; en judíos el riesgo mayor es para hipospadias; en nativos para microtia, labio leporino, polidactilia preaxial y atresia anal; en afrodescendientes para polidactilia postaxial e hipospadias y en árabes para espina bífida. En conclusión, en Sudamérica algunos grupos étnicos muestran un riesgo incrementado para ciertas anomalías congénitas, independientemente de la edad de los padres, el nivel socioeconómico y el número de embarazos, sugiriendo susceptibilidad de ciertos grupos étnicos para determinados defectos congénitos.
  • Artículo
    Acceso Abierto
    Withdrawal of dietary phytoestrogens in adult male rats affects hypothalamic regulation of food intake, induces obesity and alters glucose metabolism
    (2015) Andreoli, M.F.; Stocker, C.; Rossetti, M.F.; Alzamendi, A.; Castrogiovanni, Daniel; Luque, E.; Ramos, R.G.
    The absence of phytoestrogens in the diet during pregnancy has been reported to result in obesity later in adulthood. We investigated whether phytoestrogen withdrawal in adult life could alter the hypothalamic signals that regulate food intake and affect body weight and glucose homeostasis. Male Wistar rats fed from conception to adulthood with a high phytoestrogen diet were submitted to phytoestrogen withdrawal by feeding a low phytoestrogen diet, or a high phytoestrogen-high fat diet. Withdrawal of dietary phytoestrogens increased body weight, adiposity and energy intake through an orexigenic hypothalamic response characterized by upregulation of AGRP and downregulation of POMC. This was associated with elevated leptin and T4, reduced TSH, testosterone and estradiol, and diminished hypothalamic ERα expression, concomitant with alterations in glucose tolerance. Removing dietary phytoestrogens caused manifestations of obesity and diabetes that were more pronounced than those induced by the high phytoestrogen-high fat diet intake.
  • Artículo
    Acceso Abierto
    The methylating agent streptozotocin induces persistent telomere dysfunction in mammalian cells
    (2015) Paviolo, N.; Santiñaque, F.; Castrogiovanni, Daniel; Folle, G.; Bolzan, Agustín Eduardo
    We analyzed chromosomal aberrations involving telomeres in the progeny of mammalian cells exposed to the methylating agent and antineoplastic/diabetogenic drug streptozotocin (STZ), to test whether it induces long-term telomere instability (by chromosome end loss and/or telomere dysfunction). Rat cells (ADIPO-P2 cell line, derived from Sprague-Dawley rat adipose cells) were treated with a single concentration of STZ (2mM). Chromosomal aberrations were analyzed 18h, 10 days, and 15 days after treatment, using PNA-FISH with a pan-telomeric probe [Cy3-(CCCTAA)3] to detect (TTAGGG)n repeats. Cytogenetic analysis revealed a higher frequency of chromosomal aberrations in STZ-exposed cultures vs. untreated cultures at each time point analyzed. The yield of induced aberrations was very similar at each time point. Induction of aberrations not involving telomere dysfunction was only observed 18h and 15 days after treatment, whereas induction of telomere dysfunction-related aberrations by STZ (mainly in the form of telomere FISH signal loss and duplications, most of them chromatid-type aberrations) was observed at each time point. Our results show that STZ induces persistent telomere instability in mammalian cells, cytogenetically manifested as telomere dysfunction-related chromosomal aberrations. Neither telomere length nor telomerase activity is related to the telomere dysfunction.
  • Artículo
    Acceso Abierto
    Human population genetic structure detected by pain-related mu opioid receptor gene polymorphisms
    (2015) López Soto, Eduardo Javier; Catanesi, Cecilia Inés
    Several single nucleotide polymorphisms (SNPs) in the Mu Opioid Receptor gene (OPRM1) have been identified and associated with a wide variety of clinical phenotypes related both to pain sensitivity and analgesic requirements. The A118G and other potentially functional OPRM1 SNPs show significant differences in their allele distributions among populations. However, they have not been properly addressed in a population genetic analysis. Population stratification could lead to erroneous conclusions when they are not taken into account in association studies. The aim of our study was to analyze OPRM1 SNP variability by comparing population samples of the International Hap Map database and to analyze a new population sample from the city of Corrientes, Argentina. The results confirm that OPRM1 SNP variability differs among human populations and displays a clear ancestry genetic structure, with three population clusters: Africa, Asia, and Europe-America.
  • Artículo
    Embargado
    First evidence of chromosomal variation within Chelonoidis chilensis (Testudines: Testudinidae)
    (2015) Sánchez, J.; Alcalde, L.; Bolzan, Agustín Eduardo
    Chelonoidis chilensis is an endangered tortoise that inhabits arid regions in Argentina, Bolivia and Paraguay. Blood samples were obtained from wild specimens from the Argentinan distribution range together with samples from specimens of known morphotype but unknown provenance. Cytogenetic analysis using Giemsa staining showed that the diploid chromosome complement was 2n=52 for all twenty-five tortoises analysed. Two different karyomorphs, termed A and B, were identified, with a karyotypic formulae of 7:5:14 and 6:5:15, respectively. G-band analysis suggests that karyomorph B may originate from a chromosomal fission event involving chromosome pair 7 of karyomorph A. In addition, all specimens analysed using Fluorescence In Situ Hybridisation (FISH) with a telomeric probe showed telomeric signals only at the terminal regions of chromosomes. This evidence suggests that the karyotype of C. chilensis does not have telocentric chromosomes, and that interstitial telomeric sequences have not played a major role during the recent chromosomal evolution of this species. Our data agree with recent molecular evidence supporting the existence of one instead several species for the C. chilensis complex. Our data further suggest a possible correlation between chromosomal variation and geographical distribution: karyomorph A is present in tortoises from the Dry Chaco Eco-region, whereas karyomorph B characterises tortoises living in the Monte of Steps and Plains Eco-region. Morphology appears to vary independently of cytomorph variation.
  • Artículo
    Acceso Abierto
    Brain circuits mediating the orexigenic action of peripheral ghrelin: narrow gates for a vast kingdom
    (2015) Cabral, Agustina; De Francesco, Pablo; Perelló, Mario
    The nervous and endocrine systems act together to regulate all physiological processes essential for the body homeostasis control. Given the strict communication restrictions that the brain–blood barrier (BBB) imposes, the interplay between these two systems requires a variety of delicate anatomical interfaces and physiological mechanisms that guarantee the precise function of the neuroendocrine system as a whole. The study of the mechanisms by which hormones act in the brain in order to regulate specific neuronal populations is a research topic rather neglected. Our group studies the neuronal circuitries and molecular mechanisms by which the stomach-produced hormone ghrelin regulates appetite and other physiological functions. A clear notion of the brain targets of peripheral ghrelin is essential for the comprehensive understanding of the physiological role of this hormone. Ghrelin is called “the hunger hormone” since it is the only known orexigenic peptide hormone. The target for ghrelin orexigenic actions is the brain, which contains a variety of ghrelin-responsive nuclei; however, several evidences suggest that the accessibility of peripheral ghrelin to the brain is strikingly low. Here, we briefly summarize the current knowledge in this topic and discuss this intriguing neuroendocrinological issue.
  • Artículo
    Acceso Abierto
    Oral Metformin Treatment Counteracts Adipo-Insular Axis Dysfunction in Hypothalamic Obese Rats
    (Hindawi Publishing Corporation, 2015) Castrogiovanni, Daniel; Ongaro, Luisina; Zuburía, Guillermina; Giovambattista, Andrés; Spinedi, Eduardo
    Rats neonatally treated with monosodium L-glutamate (MSG) are deeply dysfunctional in adulthood. We explored the effect of an oral low dose of metformin treatment in male MSG rats on adipoinsular axis and visceral adipose tissue (VAT) dysfunctions, in both basal (nonfasting) and endotoxemia conditions. MSG rats, treated or not treated with metformin (30 days prior to experimentation), and control litter-mates (CTR) were studied at 90 days of age. Peripheral concentrations of glucose, lipids, and hormones were determined in basal and post-lipopolysaccharide (LPS) treatment conditions. Food intake and body weight (BW) were recorded and VAT mass and leptin mRNA levels were evaluated. Data indicated that MSG rats were lighter and displayed hypercorticosteronemia, hypophagia, adipoinsular axis hyperactivity, and enhanced VAT mass associated with an increased leptin gene expression. Interestingly, metformin-treated MSG rats corrected BW catch-up and counteracted VAT (mass and leptin mRNA level) and adipoinsular axis (basal and post-LPS) dysfunctions. Thus metformin treatment in MSG rats is able to correct several VAT and metabolic-endocrine dysfunctions. Our study suggests that a low-dose metformin therapy is effective to correct, at least in part, adipoinsular axis dysfunction in hypertrophic obese phenotypes, such as that of the human Cushing syndrome.
  • Parte de libro
    Embargado
    Genetic drift among native people from South American Gran Chaco affects interleukin 1 receptor antagonist variation
    (2015) Catanesi, Cecilia Inés; Glesmann, L.; Richardson, J.
    Genetic variation is generally responsible for ethnic differences in certain diseases, including inflammatory processes. The antagonist of cytokine IL-1, IL-1Ra, has been widely studied among Caucasian and African populations for genetic polymorphisms, and interethnic differences have been documented.However, the variation and genotype distribution of polymorphisms from these genes among South American Amerindians are thus far unknown. We present the results for a VNTR located in the IL-1Ra second intron, in a sample of 169 individuals belonging to 5 Native American populations from Argentina and Paraguay, identified as native according to their self designation, and their geographic location. We also compare this data with the results obtained from a sample of non-native Argentinian people. (Párrafo extraído a modo de resumen)